1) Field on the Invention
The present invention relates to an oxygen absorbent with functions absorbing oxygen, inorganic gases, organic gases and moisture, which is applicable to preservation of metal parts, electronic parts, electrical parts, precise parts, magnetic or optical parts, jewelry, weapons, airplanes, automobiles, glasses, rubber products, photographic films, foodstuffs, medicines, pressed flowers, paintings ancient documents and unearthed articles.
2) Prior Art
Oxygen absorbents containing metal powders, catechol, ascorbic acid, etc., as main ingredients are known. However, it has been required that such oxygen absorbents is used under a high humidity in the interior of the system since they need moisture to absorb oxygen, so that articles to be preserved have been limited. Therefore, an oxygen absorbent requiring no moisture in absorption of oxygen has been desired. Japanese Patent Publication No. 62-60936 discloses an oxygen absorbent containing an unsaturated fatty acid(s) or a fat and oil containing an unsaturated fatty acid(s) as main ingredient to be oxidized and a transition metal(s) as catalyst. Japanese Patent Kokai (Laid open) No. 4-29741 discloses an oxygen absorbent containing an aliphatic hydrocarbon(s) with an unsaturated group(s) and/or an unsaturated fatty acid compound(s) as main ingredient to be oxidized and a transition metal(s) as catalyst.
On the other hand, there has been desired an oxygen absorbent with a high performance in which an oxygen absorbing time to be required for decreasing an oxygen concentration in the interior of the system to an oxygen concentration of 0.1% or below to be able to neglect substantially oxygen is efficiently shortened. Thus, since an amount of an oxygen absorbent to be used is reduced and a size of an oxygen absorbent can be made small by improving an oxygen absorbing velocity, also from the viewpoint that recent resource saving and energy saving can be attained,it has been desired to attain such art for improvement of an oxygen absorbing velocity.
In above-mentioned prior art oxygen absorbent, an oxygen absorbing time is sharply prolonged since an oxygen absorbing velocity becomes low after absorbing a small amount of oxygen. Further, it is difficult to attempt not to contact perfectly the oxygen absorbent with oxygen during production of the oxygen absorbent. Also when the oxygen absorbent is actually applied or also when necessary amount of the oxygen absorbent is taken out from a sealed bag enclosed a specific amount of the oxygen absorbent and then remained amount of the oxygen absorbent is preserved, it is difficult to attempt to not to contact perfectly it with oxygen. Therefore, in order not to contact the oxygen absorbent with oxygen, it is necessary to handle it under an atmosphere of an inert gas such as nitrogen which results in inconvenience of its handling.